Summary

We present spectral results from a multi-satellite, broad-band campaign on the Narrow-line Seyfert 1 galaxy Ton S180
performed at the end of 1999. We discuss the spectral-energy distribution of the source, combining simultaneous Chandra, ASCA
and EUVE data with contemporaneous FUSE, HST, and ground-based optical and infra-red data. The resulting SED shows that
most of the energy is emitted in the 10 -- 100 eV regime, which must be dominated by the primary energy source. No spectral
turnover is evident in the UV regime. This, the strong soft X-ray emission, and the overall shape of the SED indicate that
emission from the accretion disk peaks between 15 and 100 eV. High resolution FUSE spectra showing UV absorption due to O
VI and the lack of detectable X-ray absorption in the Chandra spectrum demonstrate the presence of a low column density of
highly ionized gas along our line-of-sight. The highly-ionized state of the circumnuclear gas is most likely linked to the high
luminosity and steep spectrum of the active nucleus. Given the strong ionizing flux in Ton S180, it is possible that the clouds
within a few tens of light days of the central source are too highly ionized to produce much line emission. Thus the narrow width
of the emission lines in Ton S180 is due to the emission arising from large radii.